Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
2000-05-12
2001-12-11
Dudash, Diana (Department: 1619)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C424S400000, C424S401000, C424S078020, C424S078060, C424S078180, C514S937000, C514S938000, C514S939000, C514S940000, C514S941000, C514S943000
Reexamination Certificate
active
06329413
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention is directed to a skin cream containing allantoin in an oil-in-water emulsion with improved stability.
Allantoin is a commonly used ingredient in cosmetic applications, particularly for skin creams, where it exerts a skin protective function. Many such cosmetic compositions and other compositions are prepared as emulsions, particularly oil-in-water emulsions. One emulsifier system used with such compositions is a combination of sodium lauryl sulfate and beeswax. Although solutions of sodium lauryl sulfate are alkaline with an approximate pH of 9.5, the simultaneous use of beeswax with its organic acids produces a complex and neutralized system with a pH of about 6.8 to about 7.5. However, in such a system with a pH range of 6.8 to 7.5, allantoin degrades significantly with time and in accelerated stability tests at 40° C. Because cosmetics and other preparations designed for application to the skin are typically stored by users at room temperature, and room temperatures can fluctuate with climatic conditions, such a degree of stability is undesirable. Therefore, there is a need for an oil-in-water emulsified composition containing allantoin in which the stability of allantoin is increased.
In particular, there is a need for compositions that are suitable for treating a number of severe and difficult-to-treat skin conditions. One of these skin conditions is epidermolysis bullosa. This is a severe genetic skin disorder in which the skin breaks down and large blisters appear. These blisters are difficult to treat by conventional means. Other skin diseases for which improved treatments are needed are pressure ulcers, decubitus ulcers or bed sores, and diabetic ulcers, as well as milia. Therefore, improved compositions that are suitable for treating these diseases are needed.
SUMMARY
In general, a composition according to the present invention comprises an oil-in-water emulsion comprising:
(1) allantoin; and
(2) at least one anionic or nonionic emulsifier that is substantially hydrophilic and is soluble in water.
The pH of the composition is in a range of from about 5.0 to about 6.5. This pH range stabilizes the allantoin and makes storage of the composition for extended periods practical.
Typically, the at least one anionic or nonionic emulsifier is selected from the group consisting of:
(1) an acidic anionic polymer;
(2) an anionic emulsifier selected from the group consisting of sodium lauryl sulfate, sodium laureth sulfate, sodium oleyl succinate, sodium dodecylbenzenesulfonate, and sodium lauryl sarcosinate;
(3) a nonionic emulsifier that is an ethoxylated ether or an ethoxylated ester whose chain length ranges from 8 to 22 carbon atoms;
(4) glyceryl stearate;
(5) cetyl alcohol;
(6) stearic acid;
(7) sodium stearoyl lactylate;
(8) sodium isostearoyl lactylate;
(9) triethanolamine;
(10) a polyethylene glycol ether of cetearyl alcohol wherein the number of olyethylene glycol moieties in the ether is from 6 to 40; and
(11) beeswax.
The composition can further comprise a carbohydrate polymer selected from the group consisting of galactoarabinan, polygalactose, and polyarabinose. Typically, the carbohydrate polymer is galactoarabinan.
One embodiment of the present invention is a composition comprising an oil-in-water emulsion comprising:
(1) allantoin; and
(2) an emulsifier system comprising:
(a) an acidic anionic polymer; and
(b) a polyethylene glycol ester of stearic acid.
The pH of the composition is from about 5.0 to about 6.5.
Typically, in this embodiment, the acidic anionic polymer is a carboxypolymethylene polymer.
The composition can further comprise a carbohydrate polymer. Typically, the carbohydrate polymer is selected from the group consisting of galactoarabinan, polygalactose, and polyarabinose. Preferably, the carbohydrate polymer is galactoarabinan.
Another embodiment of the present invention is a composition comprising an oil-in-water emulsion comprising:
(1) allantoin; and
(2) an emulsifier system comprising:
(a) an acidic anionic polymer; and
(b) an anionic emulsifier that is substantially hydrophilic and is soluble in water, the pH of the composition being adjusted to a range of from about 5.0 to about 6.5.
The anionic emulsifier can be selected from the group consisting of sodium lauryl sulfate, sodium laureth sulfate, sodium oleyl succinate, sodium dodecylbenzenesulfonate, and sodium lauryl sarcosinate. Preferably, the anionic emulsifier is sodium lauryl sulfate.
The composition can further comprise a carbohydrate polymer selected from the group consisting of galactoarabinan, polygalactose and polyarabinose. Preferably, the carbohydrate polymer is galactoarabinan.
Another embodiment of the present invention is a composition comprising an oil-in-water emulsion comprising:
(1) allantoin;
(2) an emulsifier system comprising an acidic anionic polymer; and
(3) a base to adjust the pH of the composition to a value in a range from about 5.0 to about 5.5.
Preferably, the acidic anionic polymer is a carboxypolymethylene polymer. Preferably, the base is an organic base such as triethanolamine.
In another embodiment, the composition comprises an oil-in-water emulsion comprising:
(1) allantoin;
(2) an emulsifier system comprising:
(a) an acidic anionic polymer; and
(b) a nonionic emulsifier that is an ethoxylated ether or an ethoxylated ester whose carbon chain length ranges from 8 to 22 carbon atoms, wherein the pH of the composition is from about 5.0 to about 6.5.
In this embodiment, the emulsifier system can further comprise glyceryl stearate.
This embodiment also can include a carbohydrate polymer as described above.
In yet another embodiment of the present invention, a composition comprising an oil-in-water emulsion comprising:
(1) allantoin;
(2) an emulsifier system comprising:
(a) sodium stearoyl lactylate;
(b) sodium isostearoyl lactylate;
(c) optionally, triethanolamine;
(d) optionally, at least one nonionic emulsifier selected from the group consisting of a nonionic emulsifier that is an ethoxylated ether or an ethoxylated ester whose carbon chain length ranges from 8 to 22 carbon atoms; and
(3) an acid to adjust the pH to a range of from about 5.0 to about 5.8.
Typically, the acid is citric acid.
Still another embodiment of the present invention is a composition comprising an oil-in-water emulsion comprising:
(1) allantoin; and
(2) an emulsifier system comprising at least one polyethyleneglycol ether of cetearyl alcohol, wherein the number of polyethylene glycol moieties in the polyethyleneglycol ether of cetearyl alcohol is from 6 to 40; and
(3) an acid to adjust the pH of the composition to a range of from about 5.0 to about 5.8.
For this embodiment, the acid is typically also citric acid.
For this embodiment, the emulsifier system typically comprises ceteareth-25 and ceteareth-6.
Yet another embodiment of the present invention is a composition comprising an oil-in-water emulsion comprising:
(1) allantoin;
(2) an emulsifier system comprising:
(a) a polyethylene glycol ester of stearic acid; and
(b) glyceryl stcarate; and
(3) an acid to adjust the pH of the composition to a range of from about 5.0 to about 5.8.
Typically, in this embodiment, the number of ethylene glycol moieties in the polyethylene glycol ester of stearic acid is from 25 to 100. Preferably, the polyethylene glycol ester of stearic acid is PEG-100 stearate. Typically, in this embodiment, the acid is citric acid.
Still another embodiment of the present invention is a composition comprising an oil-in-water emulsion comprising:
(1) allantoin;
(2) a carbohydrate polymer; and
(3) an emulsifier system comprising:
(a) beeswax; and
(b) an anionic emulsifier that is substantially hydrophilic and is soluble in water;
wherein the pH of the composition is in a range from about 5.0 to about 6.5.
The carbohydrate polymer in this embodiment is as described above.
Typically, the anionic emulsifier that is substantially hydrophilic and soluble in water is selected from the group consisting of sodium lauryl sulfate, sodium laureth sulfate, sodium oleyl succinate, sodium
Alwyn Company, Inc.
Dudash Diana
Oppenheimer Wolff & Donnelly LLP
Sharareh Shahnam
LandOfFree
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